The broad goal of the proposed research is to advance our knowledge about the development of the psychological processes involved in scientific discovery. The research will be guided by a conceptualization of scientific discovery as a problem-solving process involving search in several problem spaces, the most influential of which are the space of hypotheses and the space of experiments. The focus is on developmental differences in how this dual search is executed and coordinated, and how it is influenced by both domain-specific and domain-general knowledge. The proposed empirical work involves an extensive series of laboratory studies in which subjects (preschoolers, elementary school children, high schoolers, and both science and non-science college students) attempt to discover a complex process or principle in a variety of contexts. The contexts are designed either to reflect general characteristics of real scientific discovery or to simulate some essential aspects of a specific scientific discovery. The theoretical part of the proposed work will further specify the dual-search framework and develop it into a running computational model. The proposed research program is organized around five interrelated projects, all conceived within the general framework of scientific discovery as search in problem spaces. The aim is to identify the developmental trajectory of the processes that constrain and integrate that search. Specific projects include: * Studies of pre-school children's understanding of indeterminacy. * Studies of how goals influence the formulation of hypotheses and the design of experiments. * Continued analysis of subjects' performance on very complex discovery microworlds. * Revision and extension of a framework describing the component parts of the scientific discovery process. The extended framework will have additional problem spaces will be used to organize, interpret and integrate the results of the studies. Parts of the framework will be implemented as a computational model. * Investigation of an important aspect of collaboration in science: the decision to engage or disengage from a collaboration.